Reliability assessment of silicone coated silicon concentrator solar cells by accelerated aging tests for immersing in de-ionized water

Direct de-ionized (DI) water immersion cooling has been verified to be an effective method for managing the operating temperature of silicon solar cells under concentration. However, the stable electrical performance was difficult to be achieved. The following investigation on mechanism indicated that galvanic corrosion occurred on cells. In this study, silicone coating was proposed to apply for the silicon concentrator (CPV) solar cells to eliminate or minimize the degradation when operated in DI water for a long time. The reliability of the selected silicone coatings and the silicone coated silicon CPV cells was assessed through designed accelerated aging tests, which include damp heat test, thermal cycling test and DI water immersion test. The selected silicone coatings exhibited excellent optical transparency. The tests results showed that no issues related with the selected silicone coatings’ reliability were observed. Some variations in the electrical performance of the silicone coated cells were detected, but the results gave confidence of the reliable performance of coated cells since they represented less than the total degradation allowed for the module under these tests. The simulation results indicated that temperature of the coated cell in DI water can be still maintained lower than that of conventionally encapsulated cell.